sophisticated calendar and alarm program

 Remind allows you to remind yourself of upcoming events and
 appointments. Each reminder or alarm can consist of a message sent
 to standard output, or a program to be executed.
 .
 It also features: sophisticated date calculation, moon phases,
 sunrise/sunset, Hebrew calendar, alarms, PostScript output, tcl/tk
 front-end and proper handling of holidays.
 .
 Reminders can be created by the remind scripting language or by using
 the graphical frontend package "tkremind".